I have also tried to connect to this Linux machine from a Windows machine running the BOINC Manager, but I have no idea what the password is for this client. Again, I have tried my account key, my weak account key and my account password, and they all result in the Manager doing nothing. The IP of this client is 10.10.70.1, and there is no proxy required.

Using the apt-get package instead of the BOINC package worked fine. Still can't connect using BOINC Manager from another host, but boinc_cmd is working fine, and all hosts are talking back to SETI and working on tasks.